Inula helenium aka Elecampagne

Inula helenium, or elecampane, belongs to the daisy family. This perennial herb grows from spreading rhizomes and loses its leaves seasonally. Its native range runs from southeast Europe to western Siberia and Iran. It has spread beyond gardens in eastern North America. There, it grows in fields, clearings, roadsides, and disturbed ground.

Garden plants often stand 3–6 feet [0.9–1.8 metres] tall. RHS gives a taller range, reaching 8.2 feet [2.5 metres]. Plants spread about 2–3.3 feet [0.6–1 metre] wide. The stout green stems have hairs and lengthwise grooves. Some branch near the top. Large lower leaves grow on long stalks. These leaves reach 1–2 feet [0.3–0.6 metres] long. Their edges have teeth and waves, with a clear white midvein. Rough hairs cover the upper face; softer hairs coat the underside. Smaller leaves clasp the stem higher up.

The yellow flower heads look like daisies with thin rays. They grow near stem tips and from upper leaf joints. Each head has a raised centre of tiny yellow flowers. These turn brown as they age. Leaf-like bracts surround the base of each flower head. Flowering runs from June or July through September. Bees and butterflies visit the blooms. The small brown fruits are achenes, each with fine bristles. Young plants first make a rosette of large leaves. They need a cold spell before they can flower.

Elecampane grows in sun or part shade. It prefers deep, rich soil that holds moisture but drains well. It accepts sandy soil, loam, and clay across a broad pH range. Cool summers suit it best. Sources list USDA zones 3–7 and RHS hardiness H6. Tall stems may need support where winds are strong. Leaves lose their looks soon after flowering. Trim dead foliage in autumn or early spring. Propagate through seed or division. It suits herb beds, cottage borders, and wildflower gardens. Serious pests and diseases are uncommon. However, rapid spread and persistent root pieces can make control hard.

People have long used the roots in herbal medicine. Cooked leaves have a bitter taste and an aromatic flavour. Candied roots serve as sweets, and roots also flavour absinthe. Root inulin can cause gas in some people. The roots also provide essential oil and material for blue dye. Handling the plant can cause a skin rash. PFAF warns of allergies and possible effects on diabetes and blood-pressure treatment.